［ffmpeg求助］调用avio_alloc_context()自定义write_packet发生内存泄漏

2017-02-03 11:55:36 2.8k 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

FFmpeg实战：用avformat_alloc_output_context2函数创建MP4文件，5分钟搞定基础封装本文详细解析了FFmpeg中`avformat_alloc_output_context2`函数的使用方法，帮助开发者快速掌握MP4文件封装的核心技巧。通过实战示例和常见问题排查，读者可以在5分钟内完成基础封装，提升音视频处理效率。阅读详情

劳烦各位大神帮忙看一下下面的代码有什么问题？为什么进程在运行过程中（即while(1)循环中）占用内存一直在不断增加？最终导致系统内存耗尽，无法申请新的内存。是AVIOContext结构的初始化有问题？还是哪里有问题？看了很久也没有找到原因。打印调试发现内存即将耗尽时，进程会阻塞在av_interleaved_write_frame()，最终返回错误推出循环。所以，应该是在该函数中不断申请内存又没有释放，但具体不知道是哪里申请了内存。希望大家能指点一二，感激不尽！！！



int fp_write = -1;



int write_packet(void *opaque, uint8_t *buff, int buf_size)

{

    int sentbyte = -1;

	if (fp_write != -1)

	{

		sentbyte = write(fp_write, buff, buf_size);

	}

	

    return sentbyte;

}



int main(void)

{

	int ret = 0, i;

    AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;

	AVIOContext *avio_out = NULL;

    AVPacket pkt;

#define USE_H264BSF

#ifdef USE_H264BSF

	AVBitStreamFilterContext *h264bsfc = NULL;

    int video_index = -1;

#endif

    char *in_filename, *out_filename;

	unsigned char *out_buff = NULL;



    in_filename  = "/tmp/media/mp4.mp4";

    out_filename = "/tmp/media/test_video.ts";



    av_register_all();



    if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0)

    {

        fprintf(stderr, "Could not open input file '%s'", in_filename);

        goto end;

    }



    if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0)

    {

        fprintf(stderr, "Failed to retrieve input stream information");

        goto end;

    }



	/* Allocate buffer for output data */

	out_buff = (unsigned char *)av_malloc(OUT_BUFF_LEN);

	printf("out_buff: 0x%p\n", out_buff);

	if (!out_buff)

	{

		fprintf(stderr, "av_malloc error\n");

		goto end;

	}



	/* Output file for testing */

	fp_write = open(out_filename, O_WRONLY | O_CREAT);

	if (fp_write == -1)

	{

		perror("open");

		goto end;

	}

	

	/* Allocate avformat */

	ofmt_ctx = avformat_alloc_context();

    if (!ofmt_ctx)

    {

        fprintf(stderr, "Could not create output context\n");

        ret = AVERROR_UNKNOWN;

        goto end;

    }

	ofmt_ctx->oformat = av_guess_format("mpegts", NULL, NULL);

	if (!ofmt_ctx->oformat)

	{

		fprintf(stderr, "Could not set output format\n");

        ret = AVERROR_UNKNOWN;

        goto end;

	}

	

    /* Allocate avio context */

	avio_out = avio_alloc_context(out_buff, OUT_BUFF_LEN, 1, NULL, NULL, write_packet, NULL);

	if (!avio_out)

	{

		fprintf(stderr, "Could not create avio context\n");

        ret = AVERROR_UNKNOWN;

        goto end;

	}

		

	/* AVIO struct */

	ofmt_ctx->pb = avio_out; 

	ofmt_ctx->flags = AVFMT_FLAG_CUSTOM_IO;



    for (i = 0; i < ifmt_ctx->nb_streams; i++)

    {

        AVStream *in_stream = ifmt_ctx->streams[i];

        AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);

        if (!out_stream) {

            fprintf(stderr, "Failed allocating output stream\n");

            ret = AVERROR_UNKNOWN;

            goto end;

        }



        ret = avcodec_copy_context(out_stream->codec, in_stream->codec);

        if (ret < 0) {

            fprintf(stderr, "Failed to copy context from input to output stream codec context\n");

            goto end;

        }

        out_stream->codec->codec_tag = 0;

        if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)

        {

			out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;

		}

#ifdef USE_H264BSF

		/* mark video index */

		if (out_stream->codec->codec_type == AVMEDIA_TYPE_VIDEO)

		{

			video_index = i;

		}

#endif

    }



    ret = avformat_write_header(ofmt_ctx, NULL);

    if (ret < 0)

    {

        fprintf(stderr, "Error occurred when opening output file\n");

        goto end;

    }



#ifdef USE_H264BSF

	h264bsfc = av_bitstream_filter_init("h264_mp4toannexb");

#endif

    while (1) {

        AVStream *in_stream, *out_stream;

        ret = av_read_frame(ifmt_ctx, &pkt);

        if (ret < 0)

        {

        	av_packet_unref(&pkt);

			break;

		}

#ifdef USE_H264BSF

		if (pkt.stream_index == video_index)

		{

			av_bitstream_filter_filter(h264bsfc, ifmt_ctx->streams[video_index]->codec,

				NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);

		}

#endif

        in_stream  = ifmt_ctx->streams[pkt.stream_index];

        out_stream = ofmt_ctx->streams[pkt.stream_index];



        /* copy packet */

        pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);

        pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);

        pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);

        pkt.pos = -1;



        ret = av_interleaved_write_frame(ofmt_ctx, &pkt);

		if (ret < 0) {

            fprintf(stderr, "Error muxing packet\n");

			av_packet_unref(&pkt);

            break;

        }

		

		av_packet_unref(&pkt);

    }



    av_write_trailer(ofmt_ctx);

    

end:

    avformat_close_input(&ifmt_ctx);



    /* close output */

	if (!avio_out && out_buff)

	{

		av_freep(&out_buff);

	}

	

    if (avio_out)

    {

		av_freep(&avio_out->buffer);

		av_freep(&avio_out);

		

	}

    

	if (fp_write != -1)

	{

		close(fp_write);

	}

	

	avformat_free_context(ofmt_ctx);



#ifdef USE_H264BSF

	av_bitstream_filter_close(h264bsfc);

#endif	



    if (ret < 0 && ret != AVERROR_EOF)

    {

        fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));

        return 1;

    }



	return 0;

}